Now Sheryl Sandberg is on the line.

Sandberg is going over the finances.

Sandberg is talking about mobile.

She says people spend more time on Facebook than any other app. In Q1, mobile was 30% of ad revenues. Seeing global growth, particularly in Asia. Mobile app install ads did very well. 3,800 developers used these ads to drive 25 million downloads. Of the top apps on Android and iPhone, 40% used Facebook ads. British Telcom provider O2 used Facebook mobile ad as its only marketing. It got to 9mm users.

Sandberg is talking about improving measurement

She's talking about Bud Light. Found that FB ads created a 6X return on ad spend.

Now she's talking about clicks, and how they are not a good way to measure the success of advertisements.

She says 99% of people who saw a Facebook ad and then bought the product in a store never clicked on an ad.

She's talking about new targeting tools like custom audiences, where an advertiser can target users based on their own databases (for example, a list of customers who have not returned lately). This product got 2X more usage in Q1 as Q4.

She says that Facebook can deliver ads to the 12 million people who are likely to buy a car in the next 12 months.

Analyst: Engagement was up. Why?

Analyst: What devices do you see beyond mobile? Does moving ads into the News Feed help that?

Zuckerberg: The trend of more form factors is orthogonal to the trend we see of people sharing more in more ways. They're going to use whatever technology, whether that's phones, desktops, tablets or glasses. There's going to be good ways to consume social content on all of those. We're not tooled up to make 10 huge investments. Tablets are growing quickly and that's going to be more important. Getting ads into News Feed helps because now the business model can travel into whatever new gadget.

Analyst: Wants to talk about the potential of impressions-based ads on Facebook. Also wants to know why RPU slightly decelerated

Sheryl says the focus of buying Atlas was impressions-based ads. Online, the ad that has gotten the last click has traditionally been credited for the sale with ad dollars. The focus is to connect ad impressions to activity offline and on.

Ebersman says RPU was up 21% q/q. He doesn't have anything to say about seasonality. Q4 to Q1 is always that way.

Analyst: Wants to know how Facebook sells ads in places where it is hard to sell ads

Analyst: Can you optimize ads on PC? Can you share a business update on Instagram?

Sheryl says there is room to improve ads on Facebook. Mostly in quality. "Each ad can be a better experience for users: content as good as something a user would see from a friend on the site."

Zuckerberg says that Instagram is doing really well, growing quickly. "That's the right focus for them." He says brands are putting photos into Instagram and getting great engagement. They're growing a lot faster now than Facebook was.

Analyst: Wants to know about mobile, of all things!

Zuckerberg says the people who use graph search like it, and that it's going to continue rolling out soon

Analyst: Is it true that those who are under 25 are engaging less?

Ebersman says we remain please by engagement of people of all ages. We have high penetration among people under 25. Younger users remain the most active. They are extremely active on Instagram. The urban legend flows from suveys people do, where people say they use other social sites. The fear stems from the idea that this is a zero sum game. We don't think it is.